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A forced-air system includes registers located in individual rooms through which heated air is discharged.
A forced-air system includes registers located in individual rooms through which heated air is discharged.

A forced-air central heating system is one which uses air as its heat transfer medium. These systems rely on ductwork, vents, and plenums as means of air distribution, separate from the actual heating and air conditioning systems. The return plenum carries the air from several large return grills (vents) to a central air handler for re-heating. The supply plenum directs air from the central unit to the rooms which the system is designed to heat. Regardless of type, all air handlers consist of an air filter, blower, heat exchanger/element/coil, and various controls. Like any other kind of central heating system, thermostats are used to control forced air heating systems.

Forced air heating is the type of central heating most commonly installed in North America.[1] It is much less common in Europe, where hydronic heating predominates, especially in the form of hot-water radiators.

Types

A modern forced-air heating furnace of the gas-fired variety.
A modern forced-air heating furnace of the gas-fired variety.

Natural gas/propane/oil/coal/wood

Electric

Heat pump

Hydronic coil

Sequence of operation

  1. Thermostat calls for heat
  2. Source of ignition is provided at the boiler
  3. Circulator initiates water flow to the hydronic coil (heat exchanger)
  4. Once the heat exchanger warms up, the main blower is activated
  5. When call for heat ceases, the boiler and circulator turn off
  6. Blower shuts off after period of time (depending on the particular equipment involved this may be a fixed or programmable amount of time)

See also

References

  1. ^ Allen, Edward; Thallon, Rob; Schreyer, Alexander C. (2017). Fundamentals of Residential Construction (4th ed.). Wiley. p. 410. ISBN 9781118977996.